There have been proposed pneumatic tires having an inner liner disposed beside the tire cavity as an air impermeable layer, the inner liner comprising a film formed of a thermoplastic resin as a main component instead of a conventional rubber in order to lighten the tire (see a patent document 1, for example).
Processes for producing such pneumatic tires include a process for winding a sheet-shaped film around a tire building drum of metal to form a cylindrical inner liner. Since the film has a low adhesion, adhesion between the film and the building drum is insufficient when the film has been wound around the building drum. As a result, the film is apt to fall off the building drum, and a problem is that it is difficult to wind the film around the building drum.
In order to solve the above problem, it is useful to provide a suction structure for suctioning the film on the building drum to hold it with use of negative pressure. However, it is required to newly provide the suction structure, and existing facilities can not be used without modification, which causes a problem of an increase in facility cost.
Further, the cylindrical inner liner is formed by splicing the winding-starting end and winding-finishing end of the sheet-shaped film. The film, however, has a low adhesion, and another problem is that, even if the inner liner can be formed by splicing the ends of the film, the spliced parts are easily opened when lifting is applied to the inner liner in a tire producing process.
Patent Document 1: Japanese Patent Application Kokai Publication HEI 10-35232